Antibiotics and Painkillers — AQA GCSE Biology
Medicines either treat the symptoms of disease or kill the pathogens that cause it.
Painkillers and other symptom-relief medicines
Painkillers (e.g. aspirin, paracetamol) relieve the symptoms of disease but do not kill pathogens. They do not cure the underlying infection.
Antibiotics
Antibiotics (e.g. penicillin) kill bacteria inside the body without harming body cells. They have greatly reduced deaths from bacterial diseases.
Important points:
- Specific antibiotics treat specific bacteria — the correct one must be used.
- Antibiotics do not kill viruses, because viruses live and reproduce inside cells, making them hard to target without damaging the body.
Antibiotic resistance
The emergence of antibiotic-resistant bacteria (e.g. MRSA) is a serious concern. It is caused by:
- overuse and inappropriate use of antibiotics, and
- patients not completing the course.
Resistance is reduced by not over-prescribing antibiotics, only using them when necessary, and always finishing the course. Resistance arises through natural selection: resistant bacteria survive and reproduce.
Exam tips
- Painkillers treat symptoms; antibiotics kill bacteria.
- Antibiotics do not work on viruses — explain why (viruses are inside cells).
- Explain antibiotic resistance using natural selection.
- State two ways to reduce resistance (don't over-prescribe; finish the course).